Compressor

ABSTRACT

A compressor capable of reducing operational noise thereof through the use of a low-speed motor without a deterioration of compressive capability. The compressor comprises a hermetic casing, a compressing unit having a compression chamber to compress a refrigerant, a drive unit taking the form of a low-speed motor having four or more poles and adapted to provide power required to compress the refrigerant, and a charger adapted to increase the amount of the refrigerant to be introduced into the compression chamber.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2004-95741, filed on Nov. 22, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compressor, and, more particularly, to a compressor which can reduce operational noise through the use of a low-speed motor without a deterioration of compressive capability thereof.

2. Description of the Related Art

In general, a refrigerating cycle, employed in a refrigerator, air conditioner, etc., comprises a compressor that suctions and compresses a low-pressure refrigerant and discharges the refrigerant in a high-pressure state, a condenser that condenses the high-pressure refrigerant coming from the compressor, an expander that expands the condensed refrigerant coming from the condenser, and an evaporator that evaporates the expanded refrigerant coming from the expander to transfer heat from the refrigerant to surrounding air. Here, the compressor, condenser, expander and evaporator form a closed circuit by way of refrigerant pipes.

The refrigerant circulating in the refrigerating cycle, therefore, emits heat to the surroundings while as it is condensed in the condenser, and absorbs heat of the surroundings as it is evaporated in the evaporator. Thus, the evaporator performs a cooling operation.

Considering the configuration of the compressor, it comprises a compressing unit to compress the refrigerant, and a motor to provide power required to compress the refrigerant, both the compressing unit and the motor being mounted in a hermetic casing of the compressor. The hermetic casing is provided with a suction pipe to guide the refrigerant, coming from the evaporator, into the hermetic casing and with a discharge pipe to guide the refrigerant, compressed by the compressing unit, to the condenser.

With such a configuration, the refrigerant, introduced into the hermetic casing from the evaporator by way of the suction pipe, is compressed by passing through the compressing unit based on the driving of the motor, and successively, the compressed refrigerant is discharged to the condenser by way of the discharge pipe.

As the motor for use in the compressor of the refrigerating cycle, a 2-pole motor having a commercial rotating rate of 3000 to 3600 rpm is conventionally used in consideration of the capacity of the refrigerating cycle.

However, in the case of the conventional compressor using the high-speed 2-pole motor, there is a problem that operational noise of the compressor excessively increases due to vibration generated during the high-speed rotation of the motor.

As a solution, although it is considerable to provide the compressor with a low-speed motor having two or more poles, such as a 4-pole motor, etc., having a commercial rotating rate of 1500 to 1800 rpm in order to reduce the operational noise of the compressor, this is also problematic because such a reduced rotating rate of the motor tends to deteriorate the compressive capability of the compressor, making it impossible to perform a smooth refrigerant compressing operation.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a compressor capable of reducing operational noise through the use of a low-speed motor without a deterioration of compressive capability thereof.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects may be achieved by providing a compressor comprising: a hermetic casing, a compressing unit having a compression chamber to compress a refrigerant, a drive unit taking the form of a low-speed motor having four or more poles and adapted to provide power required to compress the refrigerant, and a charger adapted to increase the amount of the refrigerant to be introduced into the compression chamber.

The charger may be driven upon receiving a driving force of the drive unit to compress the refrigerant inside the hermetic casing and to deliver the compressed refrigerant to the compression chamber.

The drive unit may include a stator affixed in the hermetic casing, a rotor located in the stator, and a rotary shaft press fitted in the rotor, the compressing unit may include a cylinder defining the compression chamber, a piston reciprocately installed in the compression chamber, an eccentric shaft unit formed at one end of the rotary shaft, and a connecting rod to connect the eccentric shaft unit to the piston, and the charger may include an auxiliary cylinder defining a charger chamber, an auxiliary piston reciprocately installed in the charger chamber, an auxiliary connecting rod to connect the auxiliary piston to the eccentric shaft unit, a suction channel to communicate the interior of the hermetic casing with the charger chamber, and a discharge channel to communicate the charger chamber with the compression chamber.

The auxiliary piston may be configured to reach a top dead point thereof before the piston of the compressing unit reaches a top dead point thereof.

The auxiliary piston may reach a bottom dead point thereof after the piston reaches the top dead point thereof, and may reach the top dead point thereof after the piston reaches a bottom dead point thereof.

The suction channel and the discharge channel may be provided, respectively, with a suction valve and a discharge valve, opening and closing operations of the suction and discharge valves being exactly opposite to each other.

The drive unit may be a 4-pole motor.

An oil sump may be defined in a lower region of the hermetic casing, and the drive unit may include a stator affixed in the hermetic casing, a rotor located in the stator, and a rotary shaft press fitted in the rotor, the rotary shaft having an oil passage to supply oil to frictional regions of the compressing unit and the rotary shaft, and an oil pickup member may be provided at a lower end of the rotary shaft to communicate an oil sump with the oil passage, and a plate-shaped vane may be press fitted in the oil pickup member, the vane having a pair of lower bent portions formed at opposite lower corners thereof to be bent in a rotating direction of the rotary shaft and a pair of upper bent portions formed at opposite upper corners thereof to be bent in an opposite direction of the rotating direction.

The drive unit may be a 4-pole motor, and the pair of upper bent portions, provided at the upper corners of the vane, may have an angle of 45°, and the pair of lower bent portions, provided at the lower corners of the vane, may have an angle of 30°.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a longitudinal sectional view showing the general configuration of a compressor in accordance with an embodiment of the present invention;

FIG. 2 is a plan sectional view of the compressor of FIG. 1;

FIG. 3 is a sectional view of a charger in accordance with an embodiment of the present invention, showing the introduction of a refrigerant inside a hermetic casing of the compressor to a charger chamber;

FIG. 4 is a sectional view of the charger of FIG. 3, showing the discharge of the refrigerant from the charger chamber to a compression chamber;

FIG. 5 is a perspective view of a vane in accordance with an embodiment of the present invention; and

FIG. 6 is a plan sectional view of the vane of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.

FIGS. 1 and 2 illustrate the general configuration of a compressor in accordance with an embodiment of the present invention. Referring to FIGS. 1 and 2, the compressor comprises a hermetic casing 1 having upper and lower casings 1 a and 1 b coupled to each other, and a compressing unit 10 adapted to compress a refrigerant and a drive unit 20 adapted to provide power required to compress the refrigerant, which are mounted in the hermetic casing 1. The hermetic casing 1 is provided at one side thereof with a suction pipe 2 to guide the refrigerant from an evaporator of a refrigerating cycle into the hermetic casing 1, and at the other side thereof with a discharge pipe 3 to discharge the refrigerant, which was compressed by passing through the compressing unit 10, to a condenser of the refrigerating cycle.

The compressing unit 10 includes a cylinder 11 internally defining a compression chamber 11 a, a piston 12 adapted to reciprocate inside the compression chamber 11 a to compress the refrigerant, a cylinder head 13 coupled to one side of the cylinder 11 to hermetically seal the compression chamber 11 a and internally defining a refrigerant discharge chamber 13 a and a refrigerant suction chamber 13 b, and a valve unit 14 provided between the cylinder 11 and the cylinder head 13 and adapted to selectively admit passage of the refrigerant from the refrigerant suction chamber 13 b to the compression chamber 11 a or from the compression chamber 11 a to the refrigerant discharge chamber 13 a. Here, the cylinder 11 is integrally formed at an upper end of a cylinder block 30 that is disposed at the upper side of a stator.

The drive unit 20 is a motor to provide a driving force to reciprocate the piston 12 inside the compression chamber 11 a. The drive unit, i.e. motor, includes a stator 21 affixed in the hermetic casing 1, a rotor 22 located in the stator 21 to be spaced apart from an inner circumference of the stator 21 by a distance and adapted to electromagnetically interact with the stator 21, and a rotary shaft 23 press fitted in the center of the rotor 22 to rotate along with the rotor 22. In the embodiment of the present invention, the motor is a 4-pole motor having a commercial rotating rate of 1500 to 1800 rpm at a frequency band of 50 to 60 Hz. In this case, the stator 21 takes the form of a 4-pole stator.

The drive unit 20, using the 4-pole low-speed motor, is able to decrease a rotating rate of the rotary shaft 23 down to approximately half of a 2-pole motor, that is employed in a conventional refrigerating cycle compressor, thereby largely reducing vibration due to the rotation of the motor. This has the effect of reducing operational noise of the compressor to a minor level that is nearly inaudible at the outside of the hermetic casing 1.

The rotary shaft 23 is axially supported in a bearing member 31 of the cylinder block 30 to protrude upward from the cylinder block 30. An eccentric shaft unit 24 and a connecting rod 25 are provided above the rotary shaft 23. The eccentric shaft unit 24 is coupled to the upper portion of the rotary shaft 23 in an eccentrically rotatable manner. The connecting rod 25 is rotatably coupled at one end thereof to the eccentric shaft unit 24 and at the other end thereof to the piston 12 in a rotatable and linearly movable manner, thereby serving to convert the eccentric rotation of the eccentric shaft unit 24 into the linear motion of the piston 12.

Between the refrigerant suction chamber 13 b and the suction pipe 2 is provided a suction muffler 41 to reduce flow noise of the refrigerant introduced into the compression chamber 11 a. Similarly, a discharge muffler 42 (See. FIG. 2) is provided between the refrigerant discharge chamber 13 a and the discharge pipe 3 to define a resonance space suitable to reduce flow noise of the refrigerant discharged from the hermetic casing 1 to the outside. The discharge muffler 42 is integrally formed with the cylinder block 30 along with the cylinder 11.

With the configuration of the compressor as stated above, if the rotary shaft 23 rotates along with the rotor 22 as the rotor 22 electromagnetically interacts with the stator 21 upon receiving electric power, the piston 12, connected to the eccentric shaft unit 24 by way of the connecting rod 25, reciprocates inside the compression chamber 11 a. Thereby, the refrigerant is introduced into the hermetic casing 1 via the suction pipe 2 and then is introduced into the refrigerant suction chamber 13 b of the cylinder head 13 after being reduced in noise by passing through the suction muffler 41. Subsequently, the refrigerant is delivered from the refrigerant suction chamber 13 b to the compression chamber 11 a to be compressed therein, and the compressed refrigerant is discharged to the outside by way of the refrigerant discharge chamber 13 a of the cylinder head 13, the discharge muffler 42 and the discharge pipe 3. As such an operation is repeatedly performed, the compressor achieves a desired compressive performance of the refrigerant.

In the embodiment of the present invention, a charger 50 is provided at one side of the cylinder block 30 opposite to the cylinder 11 and is adapted to increase the amount of the refrigerant to be introduced into the compression chamber 11 a. The charger 50 serves to compensate for a deterioration in the compressive capability of the compressor due to the reduced rotating rate of the rotary shaft 23. In this way, the compressor of the present invention is able to satisfy a refrigerant compressive capability required in a conventional refrigerating cycle, in spite of using the low-speed 4-pole motor as the drive unit 20.

When part of the refrigerant, entering the hermetic casing 1 by way of the suction pipe 2, remains in the hermetic casing 1, rather than being introduced into the refrigerant suction chamber 13 b of the cylinder head 13 by way of the suction muffler 41, the charger 50 compresses the remaining refrigerant and delivers it to the compression chamber 11 a, thereby increasing the amount of the refrigerant introduced into the compression chamber 11 a. The charger 50 is driven upon receiving the driving force of the drive unit 20 without requiring a separate drive unit, to compress and deliver the refrigerant. Now, the configuration of the charger 50 will be explained in detail with reference to FIGS. 3 and 4.

FIG. 3 illustrates a state wherein the refrigerant inside the hermetic casing is introduced into a charger chamber, and FIG. 4 illustrates a state wherein the refrigerant inside the charger chamber is delivered into the compression chamber.

Referring to FIGS. 3 and 4, the charger 50 includes an auxiliary cylinder 51, an auxiliary piston 52, an auxiliary connecting rod 53, a suction channel 54 and a discharge channel 55. The auxiliary cylinder 51 defines a charger chamber 51 a therein and is integrally formed on the cylinder block 30 at an opposite side of the discharge muffler 42 that is also integrally formed with the cylinder block 30. The auxiliary piston 52 is adapted to reciprocate inside the charger chamber 51 a to compress the refrigerant inside the charger chamber 51 a. The auxiliary connecting rod 53 is rotatably coupled at one end thereof to the auxiliary piston 52 in a ball joint manner and the other end of the auxiliary connecting rod 53 is rotatably coupled to the eccentric shaft unit 24 along with the connecting rod 25. The auxiliary connecting rod 53 forms a predetermined angle with the connecting rod 25. The suction channel 54 communicates the interior of the hermetic casing 1 with the charger chamber 51 a, and the discharge channel 55 communicates the compression chamber 11 a with the charger chamber 51 a.

Here, the suction channel 54 extends through the auxiliary cylinder 51 to communicate the interior of the hermetic casing 1 with the charger chamber 51 a, and the discharge channel 55 extends through the cylinder block 30 between the charger chamber 51 a and the compression chamber 11 a to communicate the compression chamber 11 a with the charger chamber 51 a. An exit of the suction channel 54 and an entrance of the discharge channel 55 are formed at a closed end of the charger chamber 51 a close to a top dead point of the auxiliary piston 52.

At the exit of the suction channel 54 is provided an auxiliary suction valve 54 a which opens the suction channel 54 when the auxiliary piston 52 moves to a bottom dead point, and closes the suction channel 54 when the auxiliary piston 52 moves to the top dead point. At the entrance of the discharge channel 55 is provided an auxiliary discharge valve 55 a which closes the discharge channel 55 when the auxiliary piston 52 moves to the bottom dead point and opens the discharge channel 55 when the auxiliary piston 52 moves to the top dead point. That is, operations of the auxiliary suction valve 54 a and the auxiliary discharge valve 55 a are exactly opposite to each other.

In order to allow the auxiliary piston 52 to reach the top dead point thereof before the piston 12 reaches a top head point thereof, the auxiliary piston 52 have to deliver the refrigerant, compressed in the charger chamber 51 a, to the compression chamber 11 a before the piston 12 delivers the refrigerant of the compression chamber 11 a to the refrigerant discharge chamber 13 a. To achieve more effective charge of the refrigerant, it is preferable to adjust the length of the connecting rod 25 or auxiliary connecting rod 53 or an angle between the connecting rods 25 and 53. Preferably, the eccentric shaft unit 24, having a single axis as shown in the drawings, may be modified to have a stepped structure having different two axes. Thereby, by coupling the connecting rod 25 and the auxiliary connecting rod 53 to the different axes of the stepped eccentric shaft unit, respectively, the auxiliary piston 52 is able to reach the bottom dead point or near when the piston 12 reaches the top dead point, and to reach the top dead point or near when the piston 12 reaches the bottom dead point.

Therefore, in the compressor of the present invention, simultaneously with the compression of the refrigerant inside the compression chamber 11 a based on the rotation of the rotary shaft 23, the charger 50 delivers the remaining refrigerant inside the hermetic casing 1 to the compression chamber 11 a, resulting in an increased amount of the refrigerant introduced into the compression chamber 11 a. This has the effect of preventing a deterioration in the compressive capability of the compressor even when the low-speed 4-pole motor is employed as the drive unit 20 and thus the rotary shaft 23 rotates at a low speed.

Referring again to FIG. 1, an oil sump 1 c is defined in the lower region of the hermetic casing 1 to store a predetermined amount of oil. An oil passage 23 a is defined in the rotary shaft 23 to deliver the oil from the oil sump 1 c to frictional regions of the compressing unit 10 or rotary shaft 23. To communicate the oil sump 1 c with the oil passage 23 a, an oil pickup member 60 is provided at a lower end of the rotary shaft 23.

The oil pickup member 60 has an opened upper end which is press fitted in the lower end of the rotary shaft 23 to thereby be coupled to the rotary shaft 23, and a lower end having a centrally perforated oil supply hole 61. A plate-shaped vane 70 is installed inside the oil pickup member 60 and is adapted to produce an oil swirl between the outer surface of the vane 70 and the inner circumference of the oil pickup member 60 to thereby facilitate an oil pickup operation.

Therefore, the oil of the oil sump 1 c is delivered to frictional regions of the compressing unit 10 or rotary shaft 23 along the inner circumference of the oil pickup member 60 and the oil passage 23 a by making use of a centrifugal force generated according to the rotation of the rotary shaft 23, thereby performing lubricating or cooling operations.

FIGS. 5 and 6 illustrate the configuration of the vane in accordance with an embodiment of the present invention. As shown in FIGS. 5 and 6, the vane 70 has a center body portion 71 and bent portions 72, 73, 74 and 75 formed at four corners of the vane 70. The bent portions 72, 73, 74 and 75 are divided into a pair of lower bent portions 72 and 73 formed at opposite lower corners of the vane 70 to be bent in a rotating direction of the rotary shaft 23, and a pair of upper bent portions 74 and 75 formed at opposite upper corners of the vane 70 to be bent in the opposite direction of the rotating direction of the rotary shaft 23.

The bent portions 72, 73, 74 and 75 serve to prevent a deterioration of oil pickup efficiency due to the use of the low-speed motor. That is, the bent portions 72, 73, 74 and 75 are able to effectively pick up the oil from the oil sump 1 c even when the rotary shaft 23 rotates at a low speed.

More specifically, during the rotation of the rotary shaft 23, the lower bent portions 72 and 73, bent in the rotating direction of the rotary shaft 23, are able to more effectively draw up the oil. Thereby, the upwardly drawn oil is able to be rapidly pumped up in a vertical direction by the upper bent portions 74 and 75 as it is guided to an upper end of the vane 70. In this way, the vane 70 ensures more effective pickup of the oil even in the case of the low-speed rotation of the rotary shaft 23.

Here, in consideration of the commercial rotating rate of the 4-pole motor, it is preferable that the lower bent portions 72 and 73 are bent by an angle of 30° and the upper bent portions 74 and 75 are bent by an angle of 45°. The vane 70, which is bent at the opposite left and right sides thereof to define a concave curved contour, is press fitted against the inner circumference of the oil pickup member 60 to be secured thereto in place.

In this way, the compressor of the present invention is able to prevent a deterioration of oil pickup efficiency due to the low-speed rotation of the rotary shaft 23 even when the low-speed 4-pole motor is employed as the drive unit 20.

Now, the operation and effects of the compressor according to the present invention will be explained.

First, if the rotary shaft 23 rotates along with the rotor 22 as the rotor 22 electromagnetically interacts with the stator 21 upon receiving electric power, the piston 12, connected to the eccentric shaft unit 24 by way of the connecting rod 25, reciprocates inside the compression chamber 11 a. Thereby, the refrigerant is introduced into the hermetic casing 1 via the suction pipe 2 and then is introduced into the refrigerant suction chamber 13 b of the cylinder head 13 after being reduced in noise by passing through the suction muffler 41. After that, the refrigerant is delivered to the compression chamber 11 a to be compressed therein, and the compressed refrigerant is discharged to the outside by way of the refrigerant discharge chamber 13 a of the cylinder head 13 and the discharge pipe 3. As such an operation is repeatedly performed, the compressor completes the compression of the refrigerant.

In operation, as a result of using the 4-pole motor as the drive unit 20, the rotating rate of the rotary shaft 23 decreases to approximately half of a conventional 2-pole motor. This has the effect of largely reducing vibration due to the rotation of the motor, allowing the operational noise of the compressor to be reduced to a minor level that is substantially inaudible at the outside of the hermetic casing 1.

Further, in the compressor according to the present invention, during such a refrigerant compressing operation, the refrigerant, remaining inside the hermetic casing 1, is delivered to the compression chamber 11 a by means of the charger 50, resulting in an increased amount of the refrigerant introduced to the compression chamber 11 a. This substantially prevents a deterioration in the compressive capability of the compressor due to the low-speed rotation of the rotary shaft 23 even when the low-speed 4-pole motor is employed as the drive unit 20. Furthermore, in the compressor according to the present invention, as the vane 70, provided at the respective corners thereof with the bent portions 72, 73, 74 and 75, facilitates the oil pickup operation, thereby preventing a deterioration of oil pickup efficiency due to the low-speed rotation of the rotary shaft 23 even when the low-speed 4-pole motor is employed as the drive unit 20.

For reference, although the embodiment of the present invention as stated above employs the 4-pole motor as the drive unit 20, the drive unit 20 may be freely selected from among various low-speed motors, such as a 6-pole motor, etc. In addition to the charger 50, the compressor of the present invention may be modified to increase the volume of the compression chamber 11 a or the diameter or stroke of the piston 12. Such a modification enables more effective compensation of a deteriorated refrigerant compressive capability of the compressor due to the use of the low-speed motor.

As apparent from the above description, the present invention provides a compressor which can largely reduce operational noise thereof through the use of a low-speed motor having four or more poles, thereby enabling silent operation of the compressor. Further, by virtue of a charger, the compressor of the present invention can prevent a deterioration of compressive capability thereof even when a rotary shaft rotates at a low speed.

Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A compressor comprising: a hermetic casing; a compressing unit having a compression chamber to compress a refrigerant; a drive unit taking the form of a low-speed motor having four or more poles and adapted to provide power required to compress the refrigerant; and a charger adapted to increase the amount of the refrigerant to be introduced into the compression chamber.
 2. The compressor according to claim 1, wherein the charger is driven upon receiving a driving force of the drive unit to compress the refrigerant inside the hermetic casing and to deliver the compressed refrigerant to the compression chamber.
 3. The compressor according to claim 2, wherein the drive unit includes a stator affixed in the hermetic casing, a rotor located in the stator, and a rotary shaft press fitted in the rotor, wherein the compressing unit includes a cylinder defining the compression chamber, a piston reciprocately installed in the compression chamber, an eccentric shaft unit formed at one end of the rotary shaft, and a connecting rod to connect the eccentric shaft unit to the piston, and wherein the charger includes an auxiliary cylinder defining a charger chamber, an auxiliary piston reciprocately installed in the charger chamber, an auxiliary connecting rod to connect the auxiliary piston to the eccentric shaft unit, a suction channel to communicate the interior of the hermetic casing with the charger chamber, and a discharge channel to communicate the charger chamber with the compression chamber.
 4. The compressor according to claim 3, wherein the auxiliary piston is configured to reach a top dead point thereof before the piston of the compressing unit reaches a top dead point thereof.
 5. The compressor according to claim 4, wherein the auxiliary piston reaches a bottom dead point thereof after the piston reaches the top dead point thereof, and reaches the top dead point thereof after the piston reaches a bottom dead point thereof.
 6. The compressor according to claim 5, wherein the suction channel and the discharge channel are provided, respectively, with a suction valve and a discharge valve, opening and closing operations of the suction and discharge valves being exactly opposite to each other.
 7. The compressor according to claim 1, wherein the drive unit is a 4-pole motor.
 8. The compressor according to claim 1, wherein an oil sump is defined in a lower region of the hermetic casing, wherein the drive unit includes a stator affixed in the hermetic casing, a rotor located in the stator, and a rotary shaft press fitted in the rotor, the rotary shaft having an oil passage to supply oil to frictional regions of the compressing unit and the rotary shaft, and wherein an oil pickup member is provided at a lower end of the rotary shaft to communicate an oil sump with the oil passage, and a plate-shaped vane is press fitted in the oil pickup member, the vane having a pair of lower bent portions formed at opposite lower corners thereof to be bent in a rotating direction of the rotary shaft and a pair of upper bent portions formed at opposite upper corners thereof to be bent in an opposite direction of the rotating direction.
 9. The compressor according to claim 8, wherein the charger is driven upon receiving a driving force of the drive unit to compress the refrigerant inside the hermetic casing and to deliver the compressed refrigerant to the compression chamber.
 10. The compressor according to claim 9, wherein the compressing unit includes a cylinder defining the compression chamber, a piston reciprocately installed in the compression chamber, an eccentric shaft unit formed at one end of the rotary shaft, and a connecting rod to connect the eccentric shaft unit to the piston, and wherein the charger includes an auxiliary cylinder defining a charger chamber, an auxiliary piston reciprocately installed in the charger chamber, an auxiliary connecting rod to connect the auxiliary piston to the eccentric shaft unit, a suction channel to communicate the interior of the hermetic casing with the charger chamber, and a discharge channel to communicate the charger chamber with the compression chamber.
 11. The compressor according to claim 10, wherein the auxiliary piston is configured to reach a top dead point thereof before the piston reaches a top dead point thereof.
 12. The compressor according to claim 11, wherein the auxiliary piston reaches the top dead point thereof after the piston reaches a bottom dead point thereof, and reaches a bottom dead point thereof after the piston reaches the top dead point thereof.
 13. The compressor according to claim 12, wherein the suction channel and the discharge channel are provided, respectively, with a suction valve and a discharge valve, opening and closing operations of the suction and discharge valves being exactly opposite to each other.
 14. The compressor according to claim 8, wherein the drive unit is a 4-pole motor.
 15. The compressor according to claim 8, wherein the drive unit is a 4-pole motor, and wherein the pair of upper bent portions, provided at the upper corners of the vane, have an angle of 45°, and the pair of lower bent portions, provided at the lower corners of the vane, have an angle of 30°. 